The present invention relates generally to compactly stowable and deployable structures and more particularly to those that are compatible with deployable thin-shell reflector segments. In the deployed configuration, the invention is well suited to collect or focus transmitted and received electromagnetic energy. The invention could be used in communication, radar, electromagnetic energy concentration and solar array systems. Reflector gain characterizes the deployed configuration in energy concentration applications and increases with increasing aperture area. The furled (packaged) configuration is engineered to minimize packaged volume and envelope dimensions. The invention has utility in both terrestrial and space applications.
An extensive body of prior art exists for both deployable reflectors and solar arrays. Reflector concepts are generally characterized as mesh, deformable solid surface, segmented solid surface, or a combination of these approaches. Mesh reflectors tension an open knit resilient fabric into a faceted shape that approximates the desired surface and reacts the tension with a compression structure. A precision surface requires a large number of shaping cords to pull the mesh into the desired configuration. Adjusting the surface is a labor intensive iterative process involving characterization of the surface sensitivity to shaping cord characteristics, measuring the surface shape, analysis to predict cord adjustments and performing the adjustments (see for example, U.S. Pat. No. 6,313,811). The wrap-rib mesh reflector averts some of this process by relying on precisely shaped radial ribs (e.g., U.S. Pat. No. 5,446,474) however; the resulting surface is still limited to lower frequency use due to faceting between ribs.
Solid surface deployable reflectors avoid the frequency limitation of mesh reflectors and concepts typically employ either deformable reflector surfaces or segmented rigid reflector surfaces. Deformable surface approaches include inflatable reflectors, spring-back reflectors and concertina folded reflectors. Inflatable reflectors use gas pressure to form the shape of a membrane surface. This class of reflector suffers from poor dimensional stability due to large temperature variations and high material coefficients of thermal expansion. Spring-back reflectors deform the reflector surface into a cylindrical shape compatible with launch vehicles; however, the longest packaged dimension is limited to the diameter of the reflector. Concertina folded reflectors have been proposed. Segmented reflectors split the surface into a finite number of rigid panels that are folded inward to reduce the diameter of the structure. While each panel is dimensionally stable, relative alignment of the petals is challenging and the resulting mechanisms are heavy and do not package well.
The current invention is a hybrid deformable-segmented surface support structure that is compatible with deployable thin shell reflector segments. The invention is also compatible with mesh RF reflective surfaces, tensioned solar array blankets and rolled thin film photovoltaic arrays. The invention offers better packaging and lower fabrication costs than prior art.